1. Field of the Invention
The present invention relates to equipment and methods for detecting foreign matters, particularly fibrous foreign matters, intermingled with inspection objects.
2. Description of the Background Art
Japanese Patent Application Publication No. H9-304294 discloses a surface inspection apparatus and a surface inspection method using the apparatus. The disclosed equipment includes: a stand having a complementary color relative to the surface color of an inspection object, the stand being provided so as to be situated at the back of the inspection object; a lighting unit for lighting an inspection object; a color camera for photographing the inspection object; and a processor for perceiving a foreign matter by processing a picture photographed with the camera. Also, Japanese Patent Application Publication No. H6-323999 discloses a method of distinguishing a foreign matter from an inspection object by evaluating the results of operation made using a differential circuit, a difference circuit, a judgment circuit, etc. with respect to video signals obtained using a scanning-type imaging device. However, the performance of these equipment and methods has been insufficient for detecting a thin fibrous foreign matter.